Multi-junction solar cell and method for manufacturing the same

Abstract

Disclosed is a method for manufacturing a multi-junction solar cell including forming a lower cell, depositing a metal thin film layer on the lower cell, heat-treating the metal thin film layer to form a recombination layer and an intermediate charge transport layer, and forming an upper cell on the intermediate charge transport layer. After depositing a metal thin film on top of the lower cell, the deposited metal thin film is heat-treated at a high temperature, so that metal atoms in the metal thin film diffuse to the top of the lower cell to form the recombination layer of silicide at an interface between the metal thin film and the lower cell, and at the same time, oxygen atoms diffuse into the metal thin film to form metal oxide (the charge transport layer) at a surface of the metal thin film.

What is claimed is: 
     
         1 . A method for manufacturing a multi-junction solar cell, the method comprising:
 forming a lower cell;   depositing a metal thin film layer on the lower cell;   heat-treating the metal thin film layer to form a recombination layer and an intermediate charge transport layer; and   forming an upper cell on the intermediate charge transport layer.   
     
     
         2 . The method of  claim 1 , wherein the metal thin film layer contains one of Ti, Ni, and Mo. 
     
     
         3 . The method of  claim 2 , wherein the lower cell is formed by sequentially depositing a lower electrode, a lower absorption layer, and an emitter layer,
 wherein the lower absorption layer is a silicon substrate.   
     
     
         4 . The method of  claim 3 , wherein the metal thin film layer contains one of Ni and Mo when the emitter layer is of an n-type,
 wherein the metal thin film layer contains Ti when the emitter layer is of a p-type.   
     
     
         5 . The method of  claim 4 , wherein the recombination layer formed by the heat-treatment of the metal thin film layer is made of one silicide among TiSi 2 , NiSi 2 , and MoSi 2 . 
     
     
         6 . The method of  claim 4 , wherein, in the heat-treating of the metal thin film layer, the intermediate charge transport layer formed by the heat-treatment of the metal thin film layer is made of one metal oxide among TiO 2 , NiO 2 , and MoO X . 
     
     
         7 . The method of  claim 1 , wherein the heat-treating of the metal thin film layer includes simultaneously forming the recombination layer and the intermediate charge transport layer via the heat-treatment in an oxygen atmosphere. 
     
     
         8 . A multi-junction solar cell comprising:
 a lower cell including a lower electrode, a lower absorption layer, and an emitter layer deposited sequentially;   a recombination layer disposed on the emitter layer;   an intermediate charge transport layer disposed on the recombination layer; and   an upper cell disposed on the intermediate charge transport layer and including an upper absorption layer and an upper electrode deposited sequentially.   
     
     
         9 . The multi-junction solar cell of  claim 8 , wherein a metal thin film layer is deposited on the emitter layer and then heat-treated,
 wherein metal atoms of the metal thin film layer diffuse into the emitter layer to form the recombination layer made of silicide,   wherein at a surface of the metal thin film layer, oxygen atoms diffuse into a metal thin film to form the intermediate charge transport layer made of metal oxide.   
     
     
         10 . The multi-junction solar cell of  claim 9 , wherein the lower absorption layer includes a silicon substrate,
 wherein the upper absorption layer contains perovskite.   
     
     
         11 . The multi-junction solar cell of  claim 10 , wherein the heat-treatment is performed in an oxygen atmosphere, so that the recombination layer made of the silicide and the intermediate charge transport layer made of the metal oxide are formed simultaneously.